In the past there has been a problem in providing cyclone dust separation equipment for use in various types of industrial processes which operate at extremely high temperatures as example in the range 1500.degree. F to 3000.degree. F and even higher temperatures. Such equipment must be designed to continuously withstand such temperatures or sudden surges of extremely high temperature gases and not fail. Various processes employed in industries require cyclone separators which utilize extremely high temperatures, for example coal gasification, incineration, fuel combustion and calcining.
Cyclone separators to operate effectively require a gas discharge tube or vortex finder. This gas discharge tube is located centrally within the cyclone separator and extends into the housing below the top of the separator in the conventional design of the cyclones. Thus both sides of the gas discharge or outlet tube, both exterior and the interior walls, are exposed to the extremely high temperature condition. The remainder of the cyclones can be thermally insulated internally so that commercially available steel materials can be utilized for the shell of the cyclones.
Presently no metallic materials practically or commercially available, are suitable to withstand the high temperatures in the range of 2000.degree. F to 3000.degree. F and higher to which the gas outlet tube is exposed in critical industrial processes.
Ceramic or refractory materials are commercially available to withstand such high temperatures. However, the use of the gas discharge tube made entirely of such materials encounters design, structural and other limitations which makes their use for continuous commercial processes unsuitable. The employment of gas discharge tubes made from metallic materials and insulated on both sides with ceramic or refractory materials is unsuitable since if both sides of the gas discharge tube are exposed to the high temperature the metal is trapped within the insulation materials and is subjected to the high temperature on both sides and will reach the fluid or molten temperature and fail structurally.
By means of the present invention a gas discharge tube structure has been provided whereby commonly available structural materials may be employed in the cyclone separator construction in such a fashion that the gas discharge tube may be made from commonly available metal and insulated on the interior, i.e., the hot side, by conventional refractory materials that are used in the remainder of the interior of the cyclone separator.
In order to prevent a heat build-up in the steel structural portion of the gas discharge tube where it extends below the top of the separator housing a space of annular cross section is provided. This structure is effected by an inverted frusto-conical upwardly diverging steel wall which is connected at the bottom to the bottom portion of the gas outlet tube and at the top to a flat top wall of the cyclone separator. This structure provides a space for the dissipation of heat. Within the space heat transfer fins extend radially between the exterior of the gas outlet tube and the exterior of the upwardly diverging wall and are connected to the top of the separator. They are provided to further facilitate the dissipation of heat in the afore-mentioned space to the cooler atmosphere surrounding the cyclone. These radial fins further provide additional structural strength to provide a rigid connection between the gas outlet tube and the upwardly diverging wall and the top of the cyclone separator.
The number, size, material selection and other characteristics of the heat transfer fins can be designed to maintain the temperature of the metal portion of the gas discharge tubes at levels at which the metal materials will have a long and acceptable life. Thus the instant invention solves a major problem in the design of cyclone separator equipment for use in high temperature processes where failure of metallic materials at such high temperatures is a problem.
The above features are objects of this invention and further objects will appear in the detailed description which follows and will otherwise be apparent to those skilled in the art.
For the purpose of illustration of this invention there is shown in the accompanying drawings a preferred embodiment thereof. It is to be understood that these drawings are for the purpose of example only and that the invention is not limited thereto.